Content-Type: text/html undefined method `[]' for nil:NilClass url0 = @udisplay[0] ^^^
/home/doi/www/cgi-bin/libCovers.rb:54:in `jsonld'
/home/doi/www/cgi-bin/libCovers.rb:468:in `toptabs_pc'
/home/doi/www/cgi-bin/libCovers.rb:453:in `top_tabs'
/home/doi/www/cgi-bin/libCovers.rb:480:in `top_html'
/home/doi/www/cgi-bin/libCovers.rb:144:in `display_pc'
/home/doi/www/cgi-bin/libCovers.rb:45:in `run'
/home/www/www/doi/cgi-bin/covers.pl:83:in `main'
/home/www/www/doi/cgi-bin/covers.pl:87:in `
'